Create Private Server for a game - allowed? (Right)

My question today is whether it is possible to create a private server from an (online role) game and even play it.

The server would not be put online (if it can). It would only, I play on the server and the client would not be offered for download.

As far as I know do game companies only slightly against a private server when it is too large and thus lost too many players. I am concerned however about whether it is even legal (or not allowed) to create a private server. I think that you can not go to a server if it is not online and this officially does not exist.

I hope you can help me. Merry Christmas ;)

The best answer

If it is not public, dan yes, when it comes to the Internet, it idt illegal

You're not even that. Since you do not own the rights to the game. But as long as you do not charge for it, the developers take most little about it.